Honey, its never to late. you can get them any time of the season. i know its hard to convince parents(im a parent!), but all you need is some money to make this all happen. you'll have to buy the chicks. you'll have to buy/make a coop. you'll have to buy them food, its alot of work in the beggining, but it will pay off. for starting, i suggest getting 1-5 chicks. go 2 www.mypetchicken.com and they're you can buy some chicks WHEN U R READY!! not now, just get premission first and stuff.

The feed stores tend to only carry them in the spring. But i believe the hatcheries sell all year long. You just don't want to have them shipped in extreme weather conditions. But i hatched my showgirls in January/February of this year, and they did fine.

I just bought some chicks and guineas at the feed store today... A lot depends on where you live, too. You don't want to buy chicks in October if you live in a northern state because then you would be looking at having chicks in your house all winter. But here in North Dakota, I have bought chicks in early September and they were fine when the snow flew.
If you keep their pen clean, there should be no problem with smell. I pile it into a compost pile and it later goes into the garden. Just make sure that you have everything ready before you get any. It isn't any fun when they need to be moved out of the brooder and you don't have the pen ready yet! I don't know where you live, but if there are predators there, you need to consider that when you make their house. For instance, if you have racoons, you need a covered pen. It's devastating when you go out and find that your beautiful birds have all been torn apart!
Good luck, they really are wonderful to have!